This invention generally relates to the area of image displays and more particularly to transparent image displays and virtual reality user interfaces.
Graphical user interfaces have become a standard for interfacing between a user and a computer. Such interfaces are in wide use in computer operating system interfaces produced by Apple, Microsoft and others. These interfaces are limited in that they are intended for interfacing between a user and a computer having a two dimensional display such as a CRT or LCD. A user activates the interface with a key board and or a pointing device such as a mouse pointing to an icon on the display. Advancements have been made with the advent of a touch screen which allows a user to approximately contact the icon or intended area of the graphical user interface in order to use the interface. However, contact with the touch screen can contaminate the display area of the screen with finger prints and other types of smudges. Also, constant physical contact with the touch screen can result in its mechanical failure. Thus, what is needed is a way to contact user interface images without contacting a keyboard or a mouse or the display itself.
Three dimensional image displays are improving. Several types of three dimensional displays are known including stereoscopic displays which display a virtual three dimensional image using filters to highlight images intended for each eye of the viewer, thereby providing a stereoscopic or three dimensional affect. Such systems alternately flash images for the left and right eye of the user and require a filter for each eye, usually included in glasses worn by the viewer. Systems are in public use which require glasses may have color filters, orthogonally polarized lenses, or actively switched lenses, and the display is correspondingly modulated with left and right eye images to provide the three dimensional effect. Furthermore, stereoscopic displays which do not require glasses have been described, descriptions are included in U.S. Pat. No. 4,987,487, Jan. 22, 1991, to Ichinose et al. entitled Method of stereoscopic images display which compensates electronically for viewer head movement, and U.S. Pat. No. 5,365,370, Nov. 15, 1994, to Hudgins entitled Three dimensional viewing illusion with 2D display. Yet another stereoscopic display system in completely contained in a head set worn apparatus as described in U.S. Pat. No. 5,673,151 Sep. 30, 1997 to Dennis entitled Image correction in a virtual reality and heads up display. The aforesaid patents are incorporated by reference. The aforesaid stereoscopic displays allow the viewer to simultaneously observe both a stereoscopic object, appearing to be generally set apart in three dimensions from the image projection means, and a physical object, such as the hand of the user, in approximately the same perceived space. What is needed is a method and apparatus by which the intersection of the physical object and the stereoscopic object can form a user interface with a computer system.
Stereoscopic headsets are capable of generating independent images for each eye and thus provide a three-dimensional virtual reality image for the viewer. Such headsets have the advantage of providing the experience of a substantially large display system, such as a movie theater screen, at a significantly reduced price and in a substantially small area. Some headsets are opaque while others are transparent. Opaque headsets entirely block the user""s view of real images normally observable when a headset is not worn. Opaque headsets have the advantage of enhancing the virtual reality image but the disadvantage of preventing the viewer from observing real images. The inability of the observer to view real images while wearing the headsets inhibits most normal social functions such as walking or having a normal conversation with others in observer""s vicinity. On the other hand, transparent headsets allows the observer to see both real images and virtual reality images projected by the headset, the virtual reality images appearing superimposed upon reality""s real images. This has the advantage of allowing the user to view reality while wearing such a headset, thus enabling the user to conduct most normal social functions such as walking or carrying on a normal conversation. However, the quality of the virtual reality image may be compromised when superimposed upon real images because the real images may distract the user from the content of the virtual reality image, thus detracting from the virtual reality experience.
Thus, what is needed is a virtual reality viewing system that provides for the advantages of both transparent and opaque viewing systems while reducing the disadvantages of both.
It is therefor an object of the invention to provide a three dimensional display system capable of determining an intersection of a physical object with a three dimensionally displayed object in a space where the three dimensional object is viewed and generating a control signal in response thereto. The control signal may cause modification of the displayed image or control another device. The display system is also capable of extending the physical object with a three dimensional extension image and then using the extended image to determine the intersection.
It is another object of the present invention to provide a transparent display system for viewing real objects beyond the display which actively obstructs transparency to enhance viewing of displayed virtual images and real images viewable through the display.